Many compounds exhibit a photovoltaic or photoconductive effect on exposure to a light source. Such compounds are typically coated, deposited or otherwise placed in very thin layers on conductive surfaces, such as on solid semiconductive surfaces of metals like germanium, gelenium, silicon and the like or combinations thereof to form heterojunctions, or on solid transparent and conductive surfaces, such as of glass, plastic or the like which has previously been coated with a transparent conductive material. For example, in the latter case, photoconductive compounds have been usefully employed as target materials in an electron tube by binding the photoconductive target material in a thin coating to the glass tube surface and thereafter exposing the tube to a visible, infrared, or ultraviolet-containing light source. Such a procedure is described in U.S. Pat. No. 2,555,001 to H. G. Lubszynski. Conventional camera tubes prepared in this fashion have been of the "Vidicon" or storage-type and have operated with photoconductive materials having resistivities on the order of about 1 .times. 10.sup.12 ohm-cn. Recently it has become apparent that in certain applications, particularly when working at low light levels, it would be highly desirable to operate a camera tube with a photoconductive material having a resistivity on the order of 1 .times. 10.sup.6 ohm-cm. Using a material of about this order of resistivity, a photoconductive element could be prepared that would be, for practical purposes, fully conductive, or, at most, exhibit partial storage. Such "Conductron" -- type devices are described in French Pat. No. 1,008,032 to W. Veith. A material having a lower order of resistivity than about 1 .times. 10.sup.6 ohm-cm. could be employed to produce a conductive-type photoconductive element, but only at a great loss in the light sensitivity of the completed element. Up to now there has been no wholly successful effort at preparing a "Conductron"-type element.